Phase-dependent Friction of Nanoconfined Water Meniscus

Nanoscale ◽  
2021 ◽  
Author(s):  
Xin Zhao ◽  
Hu Qiu ◽  
Wanqi Zhou ◽  
Yufeng Guo ◽  
Wanlin Guo
Keyword(s):  
Ambient Conditions ◽  
Flat Substrate ◽  
Nanoconfined Water ◽  
Atomically Flat ◽  
Water Meniscus

A water meniscus naturally forms under ambient conditions at the point of contact between a nanoscale tip and an atomically flat substrate. Here we study the effect of the phase...

Nanolithograhpy Using Tip-Sample Material Transport Process

2005 ◽  
Vol 11 (S03) ◽  
pp. 10-13
Author(s):  
M. I. N. da Silva ◽  
B. R. A. Neves
Keyword(s):  
Water Layer ◽  
Sample Surface ◽  
Scanning Probe ◽  
Nanometer Scale ◽  
Direct Write ◽  
Water Effect ◽  
Ambient Conditions ◽  
Material Transport ◽  
Scanning Probe Lithography ◽  
Flat Substrate

Scanning Probe Microscopy (SPM) [1] has been an important tool to organize matter on the nanometer scale. It has been proved to be a powerful tool not only for imaging but also for nanofabrication. SPM-based nanofabrication comprises manipulation of atoms or molecules and SPM-based nanolithography. SPM-based nanolithography, referred to as scanning probe lithography (SPL) holds good promise for fabrication of nanometer-scale patterns as an emerging generic lithography technique that employs SPM to directly pattern nanometer-scale features under appropriate conditions. The water meniscus formation between the tip and the flat substrate, due to the water layer present on any surface of a material at ambient conditions, has been studied experimentally and theoretically [2-6] using SPM techniques. The water effect in the imaging process is well understood [2, 4, 6-8]. Dip pen nanolithogaphy (DPN) [9] is one example of a technique that uses the water effect to transfer material from the tip onto sample surface in direct-write fashion with nanoscopic resolution.

Low pH Chemical Etch Route for Smooth H-Terminated Si(100) And Study Of Subsequent Chemical Stability

1997 ◽  
Vol 477 ◽  
Author(s):  
B. J. Hinds ◽  
D. E. Aspnes ◽  
G. Lucovsky
Keyword(s):  
Optimal Solution ◽  
Native Oxide ◽  
Mechanistic Study ◽  
Ambient Conditions ◽  
Auger Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chemical Etch ◽  
Atomically Flat

ABSTRACTTo form atomically flat H-passivated Si(100) surfaces, wet chemical etching of sacrificial SiO2 layer has been examined. Roughness and chemical overlayer thickness, as monitored by ellipsometry shows a minima at an optimal solution of 1:0.5:30 HF(49wt\%):H2SO4 (98wt\%):H2O. A mechanistic study offers no evidence for a chemical smoothing from preferential non-Si(100) facet etching. Silicon planarization can be induced by rapid thermal annealing RTA of chemical oxides. The H-terminated Si(100) surfaces are found to be moderately reactive to ambient conditions as monitored by in-situ ellipsometry and Auger analysis. Atomic force microscopy (AFM) measurements show Si(100) surfaces to have a rms ∼1.0Å and Rmax values of 1.6–0.9Å. With measured roughness incorporate into ellipsometric model, a 5Å native oxide overlayer is rapidly incorporated into the Si(100) surface.

Friction of Nanoparticle-Covered Surfaces

2010 ◽  
Author(s):  
D. Sharma ◽  
Y. Yang ◽  
M. Ruths
Keyword(s):  
Self Assembly ◽  
Flat Surface ◽  
Adhesive Contact ◽  
Solid Particles ◽  
Surface Forces Apparatus ◽  
Force Microscopy ◽  
Flat Substrate ◽  
Atomic Force ◽  
Atomically Flat ◽  
Initial Results

We present preliminary results from a study of the friction of surfaces with nanoscopic roughness. Surfaces with asperities of a chosen height and average spacing were formed by self-assembly of nanometer-sized solid particles on a flat substrate. The adsorption density of particles was investigated with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM), and the suitability of these substrates for friction experiments at different length scales was evaluated. Initial results from friction experiments with a nanoparticle-covered surface in non-adhesive contact with an atomically flat surface in a surface forces apparatus (SFA) are presented.

Low-energy point-reflection EM

1995 ◽  
Vol 53 ◽  
pp. 610-611
Author(s):  
J. C. H. Spence ◽  
X. Zhang ◽  
J. M. Zuo ◽  
U. Weierstall ◽  
E. Munro ◽  
...  
Keyword(s):  
Low Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Experimental Point ◽  
Crystalline Substrate ◽  
Point Reflection ◽  
Reflection Geometry ◽  
Optical Analog ◽  
Point Projection ◽  
Atomically Flat

The limited penetration of the low-voltage point-projection microscope (PPM) may be avoided by using the reflection geometry to image clean surfaces in ultra-high vacuum. Figure 1 shows the geometry we are using for experimental point-reflection (PRM) imaging. A nanotip field-emitter at about 100 - 1000 volts is placed above a grounded atomically flat crystalline substrate, which acts as a mirror and anode. Since most of the potential is dropped very close to the tip, trajectories are reasonably straight if the sample is in the far-field of the tip. A resolution of 10 nm is sought initially. The specular divergent RHEED beam then defines a virtual source S' below the surface, resulting in an equivalent arrangement to PPM (or defocused CBED). Shadow images of surface asperities are then expected on the distant detector, out of focus by the tip-to-sample distance. These images can be interpreted as in-line electron holograms and so reconstructed (see X. Zhang et al, these proceedings). Optical analog experiments confirm the absence of foreshortening when the detector is parallel to the surface.

Diffraction from arrays of antiphase boundaries in ordered III-V alloys

1987 ◽  
Vol 45 ◽  
pp. 312-313
Author(s):  
T. S. Kuan
Keyword(s):  
High Surface ◽  
Growth Conditions ◽  
Ternary Alloys ◽  
Local Growth ◽  
Antiphase Boundaries ◽  
Surface Mobility ◽  
Ordered Phases ◽  
Diffraction Patterns ◽  
Atomically Flat ◽  
Degree Of Order

Recent electron diffraction studies have found ordered phases in AlxGa1-xAs, GaAsxSb1-x, and InxGa1-xAs alloy systems, and these ordered phases are likely to be found in many other III-V ternary alloys as well. The presence of ordered phases in these alloys was detected in the diffraction patterns through the appearance of superstructure reflections between the Bragg peaks (Fig. 1). The ordered phase observed in the AlxGa1-xAs and InxGa1-xAs systems is of the CuAu-I type, whereas in GaAsxSb1-x this phase and a chalcopyrite type ordered phase can be present simultaneously. The degree of order in these alloys is strongly dependent on the growth conditions, and during the growth of these alloys, high surface mobility of the depositing species is essential for the onset of ordering. Thus, the growth on atomically flat (110) surfaces usually produces much stronger ordering than the growth on (100) surfaces. The degree of order is also affected by the presence of antiphase boundaries (APBs) in the ordered phase. As shown in Fig. 2(a), a perfectly ordered In0.5Ga0.5As structure grown along the <110> direction consists of alternating InAs and GaAs monolayers, but due to local growth fluctuations, two types of APBs can occur: one involves two consecutive InAs monolayers and the other involves two consecutive GaAs monolayers.

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions
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